1. Field Of The Invention
This invention relates generally to improvements in marine seismic prospecting, and more particularly, but not by way of limitation, it relates to an improved relatively rigid towing arm apparatus for maintaining a seismic transducer at a predetermined depth adjacent to an operating vessel.
2. Description Of The Prior Art
In the field of marine seismic exploration, transducers of various types are typically towed adjacent an operating vessel. Various cables and conduits typically must be arranged between power and control sources on the operating vessel and the transducer being towed adjacent the operating vessel.
In earliest times, these power and control connections were typically made by way of flexible conduits running from the operating vessel to the transducer.
In more recent times, elongated stiff leg towing members have been utilized such as that disclosed in U.S. Pat. No. 3,452,357 to Clynch, and assigned to the assignee of the present invention.
In Clynch U.S. Pat. No. 3,452,327, a marine seismic source support is disclosed which maintains a seismic transducer in a rigid downward trailing attitude from the operating vessel. The Clynch apparatus includes a hollow, elongated stiff leg member which is generally wing shaped such that it can be supported from the operating vessel and allowed to cut through the water with very little resistance. The stiff leg member contains a plurality of conduits which extend the length thereof. The upper end of the stiff leg member is flexibly connected by chains or cables to a swivel block which is pivotally affixed at the vessel deck level. The swivel block receives operating power via flexible connectors between ship mounted power sources and the swivel block. A group of flexible conduits extends from the swivel block to the upper end of the stiff leg member where they are attached to ends of appropriate ones of the plural conduits of the stiff leg member. The lower end of the stiff leg member is secured again by chains or cables in a supporting fashion to the seismic transducer, while additional flexible conduits connect the respective lower ends of the stiff leg conduits to their proper input ports or fixtures about the seismic transducer.
In the Clynch apparatus, there is no rigid structural member for controlling torsional or rotational movement of the stiff leg member about its longitudinal axis.